Actix/Diesel API not responding to requests from Postman - rust

Question

My code seems to be ok, as it properly compiles and is quite simple. But when I run my app with cargo run, even though the program executes properly and outputs some debug printlns, it won't answer to any request.
This is my main.rs:
use actix_web::{web, App, HttpServer};
use diesel::r2d2::{ConnectionManager, Pool};
use diesel::sqlite::SqliteConnection;
use dotenvy::dotenv;
#[path = "api/books/books_handlers.rs"]
mod books_handlers;
#[path = "api/books_relationships/books_relationships_handlers.rs"]
mod books_relationships_handlers;
mod models;
mod routes;
mod schema;
mod logger;
#[actix_rt::main]
async fn main() -> std::io::Result<()> {
// Load .env file and set initialization variables
dotenv().ok();
std::env::set_var("RUST_LOG", "actix_web=debug");
let database_url = std::env::var("DATABASE_URL").expect("DATABASE_URL must be set");
// Create db connection pool with SQLite
let manager = ConnectionManager::<SqliteConnection>::new(database_url);
let pool: Pool<ConnectionManager<SqliteConnection>> = r2d2::Pool::builder()
.build(manager)
.expect("Failed to create pool.");
// Start HTTP server and register routes
println!("Starting server at http://localhost:8080");
HttpServer::new(move || {
App::new()
.app_data(pool.clone())
// Book class
.route("/create_book", web::post().to(books_handlers::create_book_handler))
.route("/list_books", web::get().to(books_handlers::list_books_handler))
.route("/get_book/{id}", web::post().to(books_handlers::read_book_by_id_handler))
.route("/update_book/{id}", web::put().to(books_handlers::update_book_handler))
.route("/delete_book/{id}", web::delete().to(books_handlers::delete_book_handler))
// BookRelationships class
.route("/create_book_relationship", web::post().to(books_relationships_handlers::create_book_relationship_handler))
.route("/list_book_relationships", web::get().to(books_relationships_handlers::list_books_handler))
.route("/get_book_relationship/{id}", web::post().to(books_relationships_handlers::read_book_by_id_handler))
.route("/update_book_relationship/{id}", web::put().to(books_relationships_handlers::update_book_handler))
.route("/delete_book_relationship/{id}", web::delete().to(books_relationships_handlers::delete_book_handler))
})
.bind("127.0.0.1:8080")?
.run()
.await
}
This is the first handler, the one I'm trying with Postman:
pub async fn create_book_handler(book_data: web::Json<Book>, pool: web::Data<DbPool>) -> HttpResponse {
println!("create_book_handler: {:#?}", book_data); // <-- this never gets executed
let result = books_dao::create_book(book_data, pool).await;
match result {
Ok(book) => {
println!("create_book_handler, OK. Book: {:#?}", book);
HttpResponse::Ok()
.content_type(ContentType::json())
.json(&book)
},
Err(err) => {
println!("create_book_handler, ERROR: {:#?}", err);
log(LogType::Error, err.to_string());
HttpResponse::InternalServerError()
.content_type(ContentType::json())
.body("{err: 'Unable to insert book into database'")
}
}
}
Then the code executes this function, calling Diesel and altering the DB:
pub async fn create_book(book: web::Json<Book>, pool: web::Data<DbPool>) -> Result<usize, Error> {
let mut conn = pool
.get()
.expect("Failed to get database connection from pool");
diesel::insert_into(books::table)
.values(book.into_inner())
.execute(&mut conn)
}
But the problem seems to be even before: not even the println! at the beginning of the handler get executed. When I start the app and send a POST request to http://127.0.0.1:8080/create_book, I get the following error in Postman:
Requested application data is not configured correctly. View/enable debug logs for more details.
Am I sending the requests in a wrong way, or is the API malfunctioning?

Answer 1

The DbPool is wrapped incorrectly. It should look like
...
App::new()
.app_data(actix_web::web::Data::new(pool.clone()))
...
This correctly wraps the DB Pool in the smart pointer that the route handlers can then use across your application